Why? I'm not saying go is a bad language at all, it has a lot of good points, as outlined in the source of this discussion. It is however not a perfect language and as such, it never hurts to criticize it, if only in the hope that it will improve in the future. I personally find the mental model required for go quite abrasive, but that's only me, and I won't hold it as valid criticism.

The alternatives vary according to the issue you want to tackle, so I would be hard pressed to recommend a particular one. And go does fill some vacant spots in language space.